The Steelers' offensive line is new, though not necessarily improved. It remains a work in progress entering Sunday's 4:15 p.m. game against the Baltimore Ravens at M&T Bank Stadium.

There are four new starters this season, including two who weren't in the lineup for the Sept. 7 opener against the Houston Texans.

Lack of continuity and familiarity are two primary characteristics of the Steelers' rebuilt line. But in-season injuries to left tackle Marvel Smith and right guard Kendall Simmons were key setbacks.

Of the two, only Smith has any chance of returning this season, and the likelihood of that happening is tenuous at best.

Without Simmons and Smith, the Steelers have turned to rookie Darnell Stapleton at guard and veteran Max Starks, who lost his starting job last season, at tackle. The Steelers also have a first-year starter on the line in guard Chris Kemoeatu, while veteran center Justin Hartwig is in his first year with the Steelers.

Given all of the change, perhaps it's not surprising that the Steelers' running game ranks 23rd in the NFL, averaging 103.8 yards per game. The ranking is their lowest since 2003, when they were 31st out of 32 teams and averaged 93 yards.

Smith will miss his ninth consecutive game as he continues to recover from a back injury. Simmons suffered an Achilles injury in the fourth game and is out for the season.

"Absolutely," coach Mike Tomlin said when asked if he remains hopeful of Smith's return. "Marvel's a quality player and a quality person. We're going to need all we can use down the stretch. We're as hopeful as he is."

Smith didn't sound as hopeful as his coach about playing again this season. He said he wants to play, but he won't take the field until he is cleared medically.

"It feels better every day," Smith said. "If I could play, whenever they give me the go-ahead, I definitely want to."

Smith hasn't practiced with the team in over two months. He works out regularly, but he still hasn't increased his work load to include Football drills.

"Walking around every day, it's fine," he said. "But when you get out on the field and have to do what I do, I'm just not going to do it as of right now."

Smith said not playing has been difficult. He continued to play last season until undergoing back surgery that caused him to miss four games along with the playoff game against Jacksonville.

"It's weird, because people think when you're hurt, you don't really do much," he said. "You're working even harder when you're hurt because you've got to rehab and do so much more to stay in shape and get your body healthy. It's frustrating in that regard. Plus, not being able to help the team. We've got a good team. It makes it that much tougher."

An unrestricted free agent after the season, it is possible Smith has played his last game for the Steelers - not that he is thinking that way.

"I've still got a chance to keep on playing," he said, "as long as it keeps getting better."